Streptavidin (hereinafter referred to as “SA”) is used as a substance for researches and inspections in various fields such as clinical medical care, food, and environment for the reason of the characteristics of a strong binding ability to biotin, high stability, and the like, for example. For example, in a method for detecting a target, the target is indirectly detected and determined quantitatively by detecting SA utilizing a binding among the target, biotin, and the SA, for example.
As described above, detection of SA is utilized in various fields, and various techniques for detecting SA have been studied. In the studies, it is required to construct a sensor capable of performing a simple and efficient measurement from the viewpoint of the wide use of the detection of SA (Non-Patent Document 1).